CVE-2026-53899

Description

Firefox for iOS used partial domain matching when attaching cookies to PDF requests, allowing a malicious site on a suffix domain to receive cookies belonging to the target site. This vulnerability was fixed in Firefox for iOS 152.0.

CVSS Vector

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=2042909
• https://www.mozilla.org/security/advisories/mfsa2026-56/